When it comes to Muscle Building it’s very had to separate fact from fiction, science from marketing and natural from drug induced.
In fact, The only real way to know what is possible in the realm of muscle growth WITHOUT the confounding variable of Steroid use, it to look back to BEFORE steroid use was even possible.
Eugene Sandow lived and died before the scientific discovery of Testosterone, so there is zero possibility that he was using anabolic Steroids during his lifetime (because we had no idea that Testosterone even existed).
So Sandow could be considered an example of the type of muscle that is achievable with the right training and great genetics.
John Barban investigates this very point here ==> Eugene Sandow – Guaranteed drug free bodybuilder